How could we possibly know he is the true pope if he has been underground for decades??
Lets just say a man pops out of the woodwork suddenly with some regal papal vestments and a used tiara (sold to him by Paul VI) surrounded by a handful of Bishops and calls a press conference. Let us go so far to say that he and the bishops completely profess the true faith, mass, abjure all the modern errors. Thats great, high fives all around. But by what possible criteria could we possibly determine with any certainty that he is as he claims to be the Vicar of Christ?? He has pictures? Film footage of the coronation? the skeleton of the real Paul VI liberated from the basement of the Vatican?